1. Field of the Invention
The present invention relates to a construction of louver blades, a mounting construction of said blades and an opening and closing type louver device which can prevent slip of a ratchet as a driving mechanism to simply and accurately adjust engagement between the blades.
2. Description of Prior Art
The opening and closing type louver device is generally composed of a louver having a number of blades journaled in parallel on a frame and a driving mechanism for opening and closing the louver, wherein a common reciprocating rod mounted on driving arms supported on shafts of the blades is reciprocated through a connecting rod mounted on a ratchet, the blades are rotated and opened while maintaining the same relative position to admit the rays of the sun or the blades are closed to engage side edge plates of blades adjacent to each other. With this arrangement, the louvers may be used for roofs, sunshades, etc., and therefore, the louvers are widely used for the roof eaves, roofs for terraces, and others.
In the opening and closing louver device, the louver is freuently opened and closed, and thus, the blade is fitted in the hollow shaft, and the idle shaft and driving shaft, which are provided to open and close the blades, associated with the driving mechanism through the driving arm tend to wear. Therefore, the device poses a significant problem in that even if such a wear is insignificant, the idle shaft or driving shaft slips within the hollow shaft and as the result, the blades cannot be opened or closed.
In case of rain, the louver is closed to serve as a roof, and therefore, the louver needs to exclude rainwater or the like. When the louver is closed, side edges of adjacent blades are in engagement with each other with a gap. Despite the presence of a considerable engaging depth of the side edges, water sometimes enters through said engaging portion to produce a water leakage, which is a problem to be solved.
The ratchet is provided with an anti-reverse mechanism, and even if wind acts on the blades of the louver in a reversing direction of the ratchet, said anti-reverse mechanism overcomes the wind force to prevent flapping blades. However, an anti-slip mechanism of the ratchet is not particularly provided with respect to the forward rotating direction, and there is a problem that reliance is merely made on the frictional force between a feed pawl or an anti-reverse pawl and a curved surface of a gear of the ratchet.
There is a further problem that due to the frequent occurrence of working allowable errors in louver constituting members, mounting errors made when the device is installed at the site and the like, it is necessary to provide an adequate engaging state of blades while pushing the reciprocating rod rightwards or pulling it leftwards to rotate the blades, at the closed position of the opening and closing louver device after the latter has been installed, which requires extremely cumbersome operation and leads to a damage of the driving mechanism.